Anionic polymerization process, and process for producing a polymer by the anionic polymerization process

ABSTRACT

In anionic polymerization using an anionic polymerization initiator, a tertiary organoaluminum compound (A) having in the molecule thereof a chemical structure represented by a general formula: Al—O—Ar wherein Ar represents an aromatic ring, and at least one Lewis base (B) selected from the group consisting of an ether compound and a tertiary polyamine compound are caused to be present in the polymerization system. In this way, the polar monomer can be polymerized with a high polymerization initiation efficiency and a high living polymerization property and at a high polymerization rate even if the used polymerization initiator is suitable for industrial use and a relatively mild cooling condition or a temperature condition near room temperature is adopted as a polymerization temperature condition.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an anionic polymerizationprocess of polymerizing an anionic polymerizable monomer with an anionicpolymerization initiator, and a process for producing a polymer usingthis polymerization process.

[0003] 2. Related Art of the Invention

[0004] Various investigations have been made on a process of subjectinga polar monomer such as a methacrylic acid ester or an acrylic acidester to anionic polymerization. However, such a polar monomer has amoiety which receives nucleophilic attack easily, such as a carbonylgroup. Upon anionic polymerization for the polar monomer, therefore, itis relatively difficult that a high living polymerization property isexhibited since there arises a side reaction of the monomer or anintermolecular cyclization reaction (so-called back biting) at thegrowing terminal of the resultant polymer.

[0005] It is suggested that when a polar monomer is subjected to anionicpolymerization using an organolithium compound as a polymerizationinitiator, an organoaluminum compound is caused to be present in thepolymerization system. According to this manner, the organoaluminumcompound coordinates to the growing terminal. Thus, the growing terminalcan be stabilized so that its nucleophilicity can be lowered. As aresult, it appears that the living polymerization property upon thepolymerization can be raised. As processes for performing anionicpolymerization of a polar monomer in the presence of an organoaluminumcompound, using an organolithium compound as a polymerization initiator,the following processes (1)-(6) are reported:

[0006] (1) a process of performing a polymerization reaction of amethacrylic acid ester in the presence of an organoaluminum compoundsuch as trialkylaluminum or dialkyl(diphenylamino)aluminum in anaromatic hydrocarbon solvent, using t-butyllithium as a polymerizationinitiator (JP-B-H7-57766),

[0007] (2) a process of polymerizing a methacrylic acid ester in thepresence of a specific organoaluminum compound having one or more bulkygroups (for example, triisobutylaluminum ordiisobutyl(2,6-di-t-butyl-4-methylphenoxy)aluminum) in a hydrocarbonsolvent, using an organolithium compound such as t-butyllithium as apolymerization initiator (U.S. Pat. No. 5,180,799),

[0008] (3) a process of polymerizing methyl methacrylate in the presenceof an organoaluminum compound, such asmethylbis(2,6-di-t-butylphenoxy)aluminum,ethylbis(2,6-di-t-butylphenoxy)aluminum,isobutylbis(2,6-di-t-butylphenoxy)aluminum ortris(2,6-di-t-butylphenoxy)aluminum, in an aromatic hydrocarbon solvent,using an organolithium compound as a polymerization initiator (U.S. Pat.No. 5,656,704),

[0009] (4) a process of polymerizing a methacrylic acid ester or anacrylic acid ester in the presence ofmethylbis(2,6-di-t-butylphenoxy)aluminum orethylbis(2,6-di-t-butylphenoxy)aluminum in toluene, using t-butyllithiumas a polymerization initiator (Polymer Preprints, Japan, Vol. 46, No. 7,pp. 1081-1082 (1997) and Polymer Preprints, Japan, Vol. 47, No. 2, p.179 (1998)),

[0010] (5) a process of polymerizing methyl methacrylate in the presenceof trialkylaluminum in toluene, using t-butyllithium as a polymerizationinitiator (Makromol. Chem., Supplement. Vol. 15, pp. 167-185 (1989)),and

[0011] (6) a process of polymerizing methyl methacrylate in the presenceof diisobutyl(2,6-di-t-butyl-4-methylphenoxy)aluminum in toluene, usingt-butyllithium as a polymerization initiator (Macromolecules, Vol. 25,pp. 5907-5913 (1992)).

[0012] Furthermore, it is reported that when a polar monomer issubjected to anionic polymerization in the presence of an organoaluminumcompound using an organolithium compound as a polymerization initiator,a certain additive is caused to be present in the polymerization systemso that the rate of the polymerization can be increased or so thatuniformity of the polymerization is improved and the molecular weightdistribution of the resultant polymer can be narrowed. Such reports are,for example, about the processes (7) and (8).

[0013] (7) When a methacrylic acid ester is polymerized in the presenceof trialkylaluminum in toluene using t-butyllithium as a polymerizationinitiator, the rate of the polymerization is improved and the molecularweight distribution of the resultant polymer is narrowed by adding tothe polymerization system an ester compound, such as methyl pivalate ordiisooctyl phthalate, in an amount of about 10% by weight of toluene(solvent). In the case in which a crown ether such as 12-crown-4 isadded instead of the ester compound, the same improvement effects areexhibited. However, in the case in which tetrahydrofuran,1,2-dimethoxyethane, N-methylpyrrolidine or the like is caused to bepresent instead of the ester compound, the improvement effects are notexhibited (Macromolecules, Vol. 31, pp. 573-577 (1998)).

[0014] (8) When a methacrylic acid ester or an acrylic acid ester ispolymerized in the presence of an organoaluminum compound such astrialkylaluminum in a hydrocarbon solvent using an organolithiumcompound such as ethyl α-lithioisobutyrate or t-butyllithium as apolymerization initiator, the rate of the polymerization is improved andthe molecular weight distribution of the resultant polymer is narrowedby adding to the polymerization system an ether compound such astriethylene glycol dimethyl ether (triglyme), dimethoxyethane or crownether, or an organoquaternary salt such as tetraalkylammonium halide ortetraphenylphosphonium halide (International publication: WO98/23651).

[0015] As described as the above-mentioned processes (1)-(8), varioussuggestions are made on processes of anionic polymerization of a polarmonomer in the presence of an organolithium compound and anorganoaluminum compound. However, the polymerization initiators that areactually used in these processes are limited to specific compounds suchas t-butyllithium and ethyl α-lithioisobutyrate. This would be becauseit is considered that a high polymerization initiation efficiency and ahigh polymerization rate can be attained. However, t-butyllithium hasmighty self-ignition ability, and has problems about safety thereof andhandling performances upon transportation, storage and the like.Concerning ethyl α-lithioisobutyrate, an operation for synthesizing itand a subsequent purifying operation are complicated. For these reasons,it is difficult to say that these polymerization initiators, which makeit possible to attain a high polymerization initiation efficiency and ahigh polymerization rate, are suitable for use in an industrial scale.Besides, examples of specific experiments reported as the processes(1)-(8) include examples wherein polymerization initiation efficiency isinsufficient for practical use.

[0016] In the case in which a polar monomer such as a methacrylic acidester or an acrylic acid ester is block-copolymerized with anothermonomer, a living polymer resulting from the polymerization of the onemonomer needs to have such a high living polymerization property thatcauses the polymerization of the other monomer to start. However, inorder to exhibit such a high living polymerization property upon anionicpolymerization in the presence of an organolithium compound and anorganoaluminum compound, it is necessary in many cases to set thetemperature upon the polymerization to a very low temperature, forexample, about −60° C. In such polymerization operation at a very lowtemperature, many facilities become necessary for cooling. Thus,industrial adoption of this operation is disadvantageous. Moreover, inthe case in which an ester of a primary alcohol and acrylic acid, suchas n-butyl acrylate, is used as the polar monomer upon polymerization,the living polymerization property upon the polymerization becomesespecially low. By the inventors' investigations, the following resultswere obtained: when an ester of a primary alcohol and acrylic acid waspolymerized in a reaction system in the presence of trialkylaluminum anda crown ether or an organoquaternary salt as reported as the process (8)at a very low temperature of about −78° C., the living polymerizationproperty of the resultant polymer of the acrylic acid ester was lost;therefore, in the case wherein the polymer was subsequently brought intocontact with another polar monomer such as methyl methacrylate, nopolymerization was able to start. Furthermore, in the case in which anacrylic acid ester is polymerized at a very low temperature as describedabove, the resultant polymer of the acrylic acid ester has highsteroregularity and high crystallinity. Thus, the polymer may beinsufficient in flexibility. Therefore, in order to obtain an acrylicacid ester polymer having excellent flexibility, it is not preferred toperform the polymerization reaction at a very low temperature asdescribed above. From these standpoints, there has not yet been found anindustrially-profitable process for producing a block copolymer of apolar monomer, such as a methacrylic acid ester or an acrylic acidester, in the actual situation.

[0017] From the above-mentioned standpoints, all of the followingrequirements are important for making anionic polymerization of a polarmonomer profitable for industrial enforcement: the rate of thepolymerization is high; the initiation efficiency of the polymerizationis high; the range of a polymerization initiator which can be used iswide; the living polymerization property upon the polymerization is high(that is, the molecular weight distribution of the resultant polymer isnarrow and the production ratio of a block copolymer in blockcopolymerization is high); and cooling conditions upon thepolymerization can be made mild.

SUMMARY OF THE INVENTION

[0018] Therefore, a problem to be solved in the present invention is toprovide in anionic polymerization of a polar monomer a polymerizationprocess making it possible to attain a high polymerization initiationefficiency and a high polymerization rate, using a polymerizationinitiator relatively excellent in safety, availability, and handlingperformances, which process makes it possible to produce a polymerhaving a relatively narrow molecular weight distribution because a highliving polymerization property can be exhibited even if a relativelyhigh polymerization temperature (that is, a relatively mild coolingcondition or a condition of a temperature near room temperature) isadopted, and which process is also useful for production of a blockcopolymer. Another problem to be solved in the present invention is toprovide an industrially-profitable process for producing a polymer,using the above-mentioned polymerization process having such advantagesdescribed as above.

[0019] The inventors made eager investigations to solve theabove-mentioned problems. As a result, it has been found that in thecase wherein, at the time of polymerizing an anionic polymerizablemonomer with an anionic polymerization initiator, a combination of aspecific organoaluminum compound and a specific Lewis base is caused tobe present in the polymerization system, it is possible to solve theproblems about the above-mentioned aptitude of the polymerizationinitiator for industrial use (the safety, availability and handlingperformances), and the problems about the above-mentioned polymerizationconditions and polymerization results (the temperature condition,polymerization initiation efficiency, polymerization rate and livingpolymerization property). Thus, the present invention has been made.

[0020] That is, a first aspect of the present invention is an anionicpolymerization process, characterized in that when an anionicpolymerizable monomer is polymerized with an anionic polymerizationinitiator, a tertiary organoaluminum compound (A) having in the moleculethereof a chemical structure represented by a general formula: Al—O—Arwherein Ar represents an aromatic ring, and at least one Lewis base (B)selected from the group consisting of an ether compound and a tertiarypolyamine compound are caused to be present in the polymerization systemwherein the polymerization is performed.

[0021] A second aspect of the present invention is a process forproducing a polymer, which comprises polymerizing an anionicpolymerizable monomer by the above-mentioned anionic polymerizationprocess (for example, a process for producing a block copolymer, whichcomprises polymerizing two or more anionic polymerizable monomers by theabove-mentioned anionic polymerization process).

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]FIG. 1 is a GPC chart of poly(n-butyl acrylate) obtained as afinal product in Example 9 according to the present invention. Itsabscissa represents efflux time.

[0023]FIG. 2 is a GPC chart of poly(n-butyl acrylate) obtained as afinal product in Reference Example 6 not according to the presentinvention. Its abscissa represents efflux time.

[0024]FIG. 3 is a GPC chart of poly(n-butyl acrylate) (a) obtained in afirst polymerization step in Example 18 according to the presentinvention, and poly(n-butyl acrylate-b-methyl methacrylate) (b) obtainedas a final product in a second polymerization step in said Example. Itshorizontal direction corresponds to efflux time.

DETAILED DESCRIPTION OF THE INVENTION

[0025] The present invention will be described in detail hereinafter.

[0026] In the anionic polymerization according to the present invention,an anionic polymerizable monomer is polymerized with an anionicpolymerization initiator.

[0027] The chemical structure of the anionic polymerizable monomer usedin the present invention is not especially limited so far as the monomerhas anionic polymerizability. However, a polar anionic polymerizablemonomer having a heteroatom such as an oxygen atom or a nitrogen atom ispreferred since the monomer can especially remarkably exhibit theadvantageous effect of the present invention. Examples of the polaranionic polymerizable monomer include vinyl monomers having a polargroup such as an α, β-unsaturated carboxylic acid ester compounds, α,α-unsaturated carboxylic acid amide compounds, α, β-unsaturated ketonecompounds and 2-vinylpyridine; and lactone compounds such asε-caprolactone. Preferred examples of the α, β-unsaturated carboxylicacid ester compound include acrylic acid esters such as methyl acrylate,ethyl acrylate, propyl acrylate, isopropyl acrylate, allyl acrylate,n-butyl acrylate, t-butyl acrylate, cyclohexyl acrylate, benzylacrylate, 2-ethylhexyl acrylate, lauryl acrylate, glycidyl acrylate,trimethoxysilylpropyl acrylate, methoxyethyl acrylate,N,N-dimethylaminoethyl acrylate and N,N-diethylaminoethyl acrylate;methacrylic acid esters such as methyl methacrylate, ethyl methacrylate,propyl methacrylate, isopropyl methacrylate, ally methacrylate, n-butylmethacrylate, t-butyl methacrylate, cyclohexyl methacrylate, benzylmethacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, glycidylmethacrylate, trimethoxysilylpropyl methacrylate, methoxyethylmethacrylate, N,N-dimethylaminoethyl methacrylate andN,N-diethylaminoethylmethacrylate; α-alkoxyacrylic acid esters such asmethyl α-methoxyacryalte and methyl α-ethoxyacrylate; crotonic acidesters such as methyl crotonate and ethyl crotonate; and 3-alkoxyacrylicacid esters such as 3-methoxyacrylic acid esters. Preferred examples ofthe α, β-unsaturated carboxylic acid amide compound include acrylamidecompounds such as N-isopropylacrylamide, N-t-butylacrylamide,N,N-dimethylacrylamide, N,N-diethylacrylamide; and methacrylamidecompounds such as N-isopropylmethacrylamide, N-t-butylmethacrylamide,N,N-dimethylmethacrylamide and N,N-diethylmethacrylamide. Preferredexamples of the α, β-unsaturated ketone compound include methyl vinylketone, ethyl vinyl ketone, methyl isopropenyl ketone, and ethylisopropenyl ketone. Among the above-mentioned monomers, especiallypreferred are acrylic acid esters, methacrylic acid esters, acrylamidecompounds and methacrylamide compounds.

[0028] One of the anionic polymerizable monomers may be used alone, ortwo or more thereof may be used in combination. There may also be used,as a part of the anionic polymerizable monomer, a monomer havingmultifunctionality wherein the molecule thereof has two or morepolymerizable groups such as a vinyl group, together with the anionicpolymerizable monomer having monofunctionality as exemplified above.Examples of the monomer having multifunctionality include ethyleneglycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropanetriacrylate, and trimethylolpropane trimethacrylate.

[0029] It is preferred that, if necessary, the anionic polymerizablemonomer used in the present invention is sufficiently dried in advanceunder an inert gas flow or the like, in order to cause thepolymerization reaction to advance smoothly. It is preferred to use adehydrating/drying agent such as calcium hydride, molecular sieves or anactivated alumina in the drying treatment.

[0030] The anionic polymerization initiator used in the presentinvention is not limited. However, the initiator is preferably anorganolithium compound having in the molecular thereof one or morecarbon atoms, which will be central anionic ion(s), and having, as thecentral counter ion(s) against the central anionic ion(s), lithiumcationic ion(s) whose number is equal to the number of the centralanionic ions. When attention is paid to the carbon atom, as the centralanionic ion(s), of the organolithium compounds, the organolithiumcompounds can be classified into three types: organolithium compoundshaving a chemical structure wherein a tertiary carbon atom is thecentral anionic ion; organolithium compounds having a chemical structurewherein a secondary carbon atom is the central anionic ion; andorganolithium compounds having a chemical structure wherein a primarycarbon atom is the central anionic ion.

[0031] Typical examples of the organolithium compound having a chemicalstructure wherein a tertiary carbon atom is the central anionic ioninclude t-alkyllithium such as t-butyllithium and1,1-dimethylpropyllithium; 1,1-diarylalkyllithium such as1,1-diphenylhexyllithium and 1,1-diphenyl-3-methylpentyllithium; and α,α-dialkyl-α-lithioacetic acid esters such as ethyl α-lithioisobutyrate,butyl α-lithioisobutyrate and methyl α-lithioisobutyrate. Examples ofthe organolithium compound having a chemical structure wherein asecondary carbon atom is the central anionic ion includesec-alkyllithium such as isopropyllithium, 1-methylpropyllithium (thatis, sec-butyllithium), 1-methylbutyllithium, 2-ethylpropyllithium and1-methylpentyllithium; cycloalkyllithium such as cyclohexyllithium;diarylmethyllithium such as diphenylmethyllithium; and1-alkyl-1-arylmethyllithium such as α-methylbenzyllithium. Examples ofthe organolithium compound having a chemical structure wherein a primarycarbon atom is the central anionic ion include n-alkyllithium such asmethyllithium, propyllithium, n-butyllithium and pentyllithium.

[0032] Among the above-mentioned organolithium compounds, theorganolithium compound having a chemical structure wherein a secondarycarbon atom is the central anionic ion is preferable from the viewpointof very good balance between convenience for industrial use (low risk ofignition, and easiness of handling and production) and polymerizationinitiation ability. Lithium salts of hydrocarbons (the number of carbonatoms: 3-40) having a chemical structure wherein a secondary carbon atomis the central anionic ion are more preferable. 1-Methylpropyllithium(that is, sec-butyllithium) is most preferable.

[0033] In the present invention, one of the anionic polymerizationinitiators may be used alone, or two or more thereof may be used incombination.

[0034] The amount of the anionic polymerization initiator in the anionicpolymerization according to the present invention is not limited.However, it is preferred in view of smooth production of a targetpolymer that the anionic polymerization initiator is used in an amountof 0.01 to 10 moles per 100 moles of the used anionic polymerizablemonomer.

[0035] In the polymerization process according to the present invention,it is important that a specific organoaluminum compound and a specificLewis base are both added to the polymerization system.

[0036] The organoaluminum compound used in the present invention is atertiary organoaluminum compound having in the molecule thereof achemical structure represented by a general formula: Al—O—Ar wherein Aris an aromatic ring. This tertiary organoaluminum compound may bereferred to “organoaluminum compound (A)” hereinafter.

[0037] The organoaluminum compound (A) used in the present invention maybe appropriately selected dependently on the kind of the used anionicpolymerizable monomer or the like. From the viewpoints of highpolymerization rate, high polymerization initiation efficiency, a widerange of a usable polymerization initiator, and high livingpolymerization property and a mild cooling condition uponpolymerization, it is preferred to use an organoaluminum compoundrepresented by the following general formula (I) or (II):

AlR¹R²R³  (I)

[0038] wherein R¹ represents a monovalent saturated hydrocarbon groupwhich may have a substituent, a monovalent aromatic hydrocarbon groupwhich may have a substituent, an alkoxy group which may have asubstituent, an aryloxy group which may have a substituent or anN,N-disubstituted amino group; R² and R³ each independently representsan aryloxy group which may have a substituent; or R² and R³may be bondedto each other to form an arylenedioxy group which may have asubstituent; or

AlR⁴R⁵R⁶  (II)

[0039] wherein R⁴ represents an aryloxy group which may have asubstituent; R⁵ and R⁶ each independently represents a monovalentsaturated hydrocarbon group which may have a substituent, a monovalentaromatic hydrocarbon group which may have a substituent, an alkoxy groupwhich may have a substituent, or an N,N-disubstituted amino group. Theorganoaluminum compounds represented by the general formulae (I) and(II) may be referred to as “organoaluminum compound (A-1)” and“organoaluminum compound (A-2)”, respectively, hereinafter. Theorganoaluminum compound (A-1) is more preferred.

[0040] Examples of the aryloxy group that may have a substituent, whichcan be represented by R¹, R², R³ or R⁴ in the general formulae (I) and(II), include aryloxy groups having no substituent, such as phenoxy,2-methylphenoxy, 4-methylphenoxy, 2,6-dimethylphenoxy,2,4-di-t-butylphenoxy, 2,6-di-t-butylphenoxy,2,6-di-t-butyl-4-methylphenoxy, 2,6-di-t-butyl-4-ethylphenoxy,2,6-diphenylphenoxy, 1-naphthoxy, 2-naphthoxy, 9-phenanthryloxy and1-pyrenyloxy groups; and aryloxy groups having a substitutent, such as a7-methoxy-2-naphthoxy group.

[0041] Examples of the arylenedioxy group that may have a substituent,which can be formed by bonding R² and R³ to each other, include groupswherein hydrogen atoms of two phenolic hydroxyl groups are removed from2,2′-biphenol, 2,2′-methylenebisphenol,2,2′-methylenebis(4-methyl-6-t-butylphenol), (R)-(+)-1,1′-bi-2-naphthol,(S)-(−)-1,1′-bi-2-naphthol or the like.

[0042] Concerning the aryloxy group which may have a substituent or thearylenedioxy group which may have a substituent, this substituent may beat least one substituent. In this case, examples of the substituentinclude alkoxy groups such as a methoxy group, an ethoxy group, anisopropoxy group and a t-butoxy group, and halogen atoms such aschlorine and bromine.

[0043] Examples of the monovalent saturated hydrocarbon group that mayhave a substituent, which can be each independently represented by R¹,R⁵ and R⁶ in the general formulae (I) and (II), include alkyl groupssuch as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,sec-butyl, t-butyl, 2-methylbutyl, 3-methylbutyl, n-octyl, and2-ethylhexyl groups; and cycloalkyl groups such as a cyclohexyl group.Examples of the monovalent aromatic hydrocarbon group that may have asubstituent, which can be each independently represented by R¹, R⁵ andR⁶, include aryl groups such as a phenyl group; and aralkyl groups suchas a benzyl group. Examples of the alkoxy group that may have asubstituent, which can be each independently represented by R¹, R⁵ andR⁶, include methoxy, ethoxy, isopropoxy, and t-butoxy groups. Examplesof the N,N-disubstituted amino group, which can be each independentlyrepresented by R¹, R⁵ and R⁶, include dialkylamino groups such asdimethylamino, diethylamino and diisopropylamino groups; and abis(trimethylsilyl)amino group. Examples of the substituent which eachof the monovalent saturated hydrocarbon group, the monovalent aromatichydrocarbon group, the alkoxy group and the N,N-disubstituted aminogroup has include alkoxy groups such as methoxy, ethoxy, isopropoxy andt-butoxy groups; and halogen atoms such as chlorine and bromine.

[0044] R¹, R² and R³ in the general formula (I) may have the samechemical structure or different chemical structures so far as thechemical structure(s) is/are within the above-defined range. In the sameway, R⁵ and R⁶ in the general formula (II) may have the same chemicalstructure or different chemical structures so far as the chemicalstructure(s) is/are within the above-defined range.

[0045] Typical examples of the organoaluminum compound (A-1) includeethylbis(2,6-di-t-butyl-4-methylphenoxy)aluminum,ethylbis(2,6-di-t-butylphenoxy)aluminum,ethyl[2,2′-methylenebis(4-methyl-6-t-butylphenoxy)]aluminum,isobutylbis(2,6-di-t-butyl-4-methylphenoxy)aluminum,isobutylbis(2,6-di-t-butylphenoxy)aluminum,isobutyl[2,2′-methylenebis(4-methyl-6-t-butylphenoxy)]aluminum,n-octylbis(2,6-di-t-butyl-4-methylphenoxy)aluminum,n-octylbis(2,6-di-t-butylphenoxy)aluminum,n-octyl[2,2′-methylenebis(4-methyl-6-t-butylphenoxy)]aluminum,methoxybis(2,6-di-t-butyl-4-methylphenoxy)aluminum,methoxybis(2,6-di-t-butylphenoxy)aluminum,methoxy[2,2′-methylenebis(4-methyl-6-t-butylphenoxy)]aluminum,ethoxybis(2,6-di-t-butyl-4-methylphenoxy)aluminum,ethoxybis(2,6-di-t-butylphenoxy)aluminum,ethoxy[2,2′-methylenebis(4-methyl-6-t-butylphenoxy)]aluminum,isopropoxybis(2,6-di-t-butyl-4-methylphenoxy)aluminum,isopropoxybis(2,6-di-t-butylphenoxy)aluminum,isopropoxy[2,2′-methylenebis(4-methyl-6-t-butylphenoxy)]aluminum,t-butoxybis(2,6-di-t-butyl-4-methylphenoxy)aluminum,t-butoxybis(2,6-di-t-butylphenoxy)aluminum,t-butoxy[2,2′-methylenebis(4-methyl-6-t-butylphenoxy)]aluminum,tris(2,6-di-t-butyl-4-methylphenoxy)aluminum, andtris(2,6-diphenylphenoxy)aluminum. Among these organoaluminum compounds(A-1), isobutylbis(2,6-di-t-butyl-4-methylphenoxy)aluminum,isobutylbis(2,6-di-t-butylphenoxy)aluminum,isobutyl[2,2′-methylenebis(4-methyl-6-t-butylphenoxy)]aluminum and thelike are especially preferred from the viewpoints of high polymerizationinitiation efficiency, high living polymerization property, easiness ofacquisition and handling, and the like.

[0046] Typical examples of the organoaluminum compound (A-2) includediethyl(2,6-di-t-butyl-4-methylphenoxy)aluminum,diethyl(2,6-di-t-butylphenoxy)aluminum,diisobutyl(2,6-di-t-butyl-4-methylphenoxy)aluminum,diisobutyl(2,6-di-t-butylphenoxy)aluminum,di-n-octyl(2,6-di-t-butyl-4-methylphenoxy)aluminum, anddi-n-octyl(2,6-di-t-butylphenoxy)aluminum.

[0047] The process for producing the organoaluminum compound (A) is notespecially limited. The compound (A) can be produced, for example,according to any known process.

[0048] In the present invention, one of the organoaluminum compounds (A)may be used, or two or more thereof may be used in combination.

[0049] The amount of the organoaluminum compound (A) in the presentinvention may be appropriately selected dependently on the kind ofpolymerization operation, the kind of a solvent constituting apolymerization system when solution polymerization is performed, othervarious polymerization conditions, and the like. In general, theorganoaluminum compound (A) is used in an amount of preferably 0.3 to300 moles and more preferably 1 to 100 moles per mole of the usedanionic polymerization initiator.

[0050] The Lewis base used in the present invention is at least oneLewis base selected from the group consisting of ether compounds andtertiary polyamine compounds. This Lewis base may be referred to as“Lewis base (B)” hereinafter.

[0051] The above-mentioned ether compound can be appropriately selectedfrom compounds which have in the molecule thereof an ether bond (—O—)and do not comprise any metal component and be used so far as thecompounds do not have an adverse effect on polymerization reaction.Preferably, the ether compound is selected from cyclic ether compoundshaving in the molecule thereof two or more ether bonds and acyclic ethercompounds having in the molecule thereof one or more ether bonds fromthe viewpoints of high effects such as high polymerization initiationefficiency and high living polymerization property upon polymerization.Specific examples of the cyclic ether compound having in the moleculethereof two or more ether bonds include crown ethers such as 12-crown-4,15-crown-5 and 18-crown-6. Specific examples of the acyclic ethercompound having in the molecule thereof one or more ether bonds includeacyclic monoether compounds such as dimethyl ether, diethyl ether,diisopropyl ether, dibutyl ether and anisole; acyclic diether compoundssuch as 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,2-diisopropoxyethane,1,2-dibutoxyethane, 1,2-diphenoxyethane, 1,2-dimethoxypropane,1,2-diethoxypropane, 1,2-diisopropoxypropane, 1,2-dibutoxypropane,1,2-diphenoxypropane, 1,3-dimethoxypropane, 1,3-diethoxypropane,1,3-diisopropoxypropane, 1,3-dibutoxypropane, 1,3-diphenoxypropane,1,4-dimethoxybutane, 1,4-diethoxybutane, 1,4-diisopropoxybutane and1,4-dibutoxybutane, 1,4-diphenoxybutane; acyclic triether compounds suchas diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether,dibutylene glycol dimethyl ether, diethylene glycol diethyl ether,dipropylene glycol diethyl ether and dibutylene glycol diethyl ether;dialkyl ethers of polyalkylene glycols such as triethylene glycoldimethyl ether, tripropylene glycol dimethyl ether, tributylene glycoldimethyl ether, triethylene glycol diethyl ether, tripropylene glycoldiethyl ether, tributylene glycol diethyl ether, tetraethylene glycoldimethyl ether, tetrapropylene glycol dimethyl ether, tetrabutyleneglycol diethyl ether, tetraethylene glycol diethyl ether, tetrapropyleneglycol diethyl ether and tetrabutylene glycol diethyl ether. Among theabove-mentioned specific examples of the ether compounds, the acyclicether compounds are preferred, and diethyl ether and 1,2-dimethoxyethaneare especially preferred since they have a little adverse effect on theorganoaluminum compound (A), they exhibit the effect of the presentinvention especially remarkably and they can easily be obtained.

[0052] If the cyclic ether compound having in the molecule thereof oneether bond, for example, tetrahydrofuran or such an epoxy compound aspropyleneoxide, is caused to be present in the polymerization systemaccording to the present invention, the ether compound may interact withthe organoaluminum compound (A) too strongly or react directly with theanionic polymerization initiator or the living polymer that is growing.In general, therefore, it is preferred to avoid the use of the cyclicether compound as the Lewis base (B).

[0053] The tertiary polyamine compound can be appropriately selectedfrom compounds having in the molecule thereof two or more tertiary aminestructures and be used so far as the compounds do not have an adverseeffect on polymerization reaction. The “tertiary amine structure” in thepresent invention means a partial chemical structure wherein threecarbon atoms are bonded to one nitrogen atom, which nitrogen atom mayconstitute a part of an aromatic ring so far as the nitrogen atom isbonded to three carbon atoms.

[0054] Preferred specific examples of the tertiary polyamine compoundinclude chain-form polyamine compounds such asN,N,N′,N′-tetramethylethylenediamine,N,N,N′,N′-tetraethylethylenediamine,N,N,N′,N″,N″-pentamethyldiethylenetriamine,1,1,4,7,10,10-hexamethyltriethylenetetraamine andtris[2-(dimethylamino)ethyl]amine; non-aromatic heterocyclic compoundssuch as 1,3,5-trimethylhexahydro-1,3,5-triazine,1,4,7-trimethyl-1,4,7-triazacyclononane and1,4,7,10,13,16-hexamethyl-1,4,7,10,13,16-hexaazacyclooctadecane; andaromatic heterocyclic compounds such as 2,2′-bipyridyl and2,2′:6′,2″-terpyridine.

[0055] It is not preferred to use a tertiary monoamine compound such astriethylamine instead of the Lewis base (B) since polymerizationinitiation efficiency and living polymerization property uponpolymerization drop.

[0056] In the present invention, any compound having in the moleculethereof one or more ether bonds and one tertiary amine structure can beregarded as the above-mentioned ether compound. Any compound having inthe molecule thereof one or more ether bonds and two or one tertiaryamine structures can be regarded as either the above-mentioned ethercompound or the above-mentioned tertiary polyamine compound. Therefore,any compound having in the molecule thereof one or more ether bonds andone or more tertiary amine structures can be used as the Lewis base (B).

[0057] In the present invention, one or more ether compounds, one ormore tertiary polyamine compounds, or both of them may be used as theLewis base(s) (B) in the present invention.

[0058] The amount of the Lewis base (B) is not limited in thepolymerization reaction according to the present invention. In order toexhibit sufficiently such effects as high polymerization initiationefficiency and high living polymerization property upon thepolymerization, the total mole number of the used Lewis base (B) ispreferably 0.1 time or more, more preferably 0.3 time or more, and mostpreferably 0.5 time or more the mole number of the used anionicpolymerization initiator. The upper limit of the amount of the Lewisbase (B) is not limited. The Lewis base (B) may be used as a solvent forpolymerization reaction. However, if the amount thereof is too large,polymerization initiation efficiency trends to drop. Therefore, in orderthat the polymerization initiation efficiency does not drop very much,it is generally preferred to set the total amount of the Lewis base (B)to 95% or less by weight of the polymerization system.

[0059] The polymerization reaction according to the present inventioncan be performed without use of an organic solvent. However, it ispreferred to perform the polymerization reaction by solutionpolymerization in an organic solvent since the temperature of thepolymerization can be controlled and conditions in the polymerizationsystem can be made uniform so as to cause the polymerization to advancesmoothly. In this case, it is generally preferred to use a hydrocarbonsolvent such as toluene, xylene, cyclohexane or methylcyclohexane, ahalogenated hydrocarbon solvent such as chloroform, methylene chlorideor carbon tetrachloride, or an ester solvent such as dimethyl phthalatebecause safety upon handling of the reagent is relatively high, thesolvent is not easily mixed with waste fluid and the solvent is easilyrecovered and purified. These organic solvents may be used either aloneor in combination of two or more thereof. It is preferred to purify theorganic solvent used in the polymerization beforehand by deaeration ordehydration.

[0060] In the case that the organic solvent is used, the amount thereofcan be appropriately adjusted dependently on the degree ofpolymerization of a target polymer, the kinds of the used monomer,anionic polymerization initiator, organoaluminum compound (A), Lewisbase (B) and solvent, and the like. In general, it is preferred to usethe organic solvent in an amount of 200 to 3000 parts by weight per 100parts of the used anionic polymerizable monomer because of smoothadvance of the polymerization, easiness of separation of the resultantpolymer, a reduction in a burden of treatment of waste fluid, and thelike.

[0061] The method of adding, to the polymerization system, the anionicpolymerization initiator, the organoaluminum compound (A), the Lewisbase (B) and the anionic polymerizable monomer is not especiallylimited. As this method, a preferred method may be appropriatelyadopted. Concerning the Lewis base (B), however, it is preferred toadopt such a manner that the Lewis base (B) contacts the organoaluminumcompound (A) before the contact with anionic polymerization initiator.The organoaluminum compound (A) may be added to the polymerizationsystem before the addition of the anionic polymerizable monomer, or maybe added thereto at the same time of the addition of the anionicpolymerizable monomer (In the latter case, the organoaluminum compound(A) and the monomer may be added in the form of a mixture thereof).

[0062] In the case that two or more anionic polymerizable monomers areused in the polymerization reaction according to the present invention,a copolymer can be obtained. In this case, any one of copolymer forms,such as random, block and tapered forms, can be produced dependently onthe method of adding the monomer (for example, simultaneous addition oftwo or more monomers, separate addition thereof at intervals of a giventime, or the like), a combination of the monomers and the like in thesame manner as in usual anionic polymerization. Since high livingpolymerization property can be exhibited according to the polymerizationprocess of the present invention, the present invention is especiallysuitable for production of a block copolymer for which a high blockingefficiency is required.

[0063] If necessary, one or more of known other additives may be addedto the polymerization system in the polymerization according to thepresent invention, as in known anionic polymerization techniques.Examples of the additives include inorganic salts such as lithiumchloride; metal alkoxide compounds such as lithium methoxyethoxyethoxideand potassium t-butoxide; and organic quaternary salts such astetraethylammonium chloride and tetraethylphosphonium bromide.

[0064] The temperature of the reaction system is not especially limitedin the polymerization according to the present invention. A suitabletemperature condition may be appropriately selected dependently on thekind of the used anionic polymerizable monomer, and the like, and beused. In many cases, a temperature within the range of −60° C. to +100°C. is preferably adopted, and a temperature within the range of −30° C.to +50° C. is more preferably adopted. If polymerization temperature istoo low upon polymerization of an acrylic acid ester, thestereoregularity of the resultant polymer becomes high so that thepolymer has crystallinity. Therefore, in order to produce an acrylicacid ester polymer having excellent flexibility, polymerizationtemperature is preferably −50° C. or higher. In the polymerizationprocess according to the present invention, cooling conditions for thepolymerization system can be made milder than in anionic polymerizationin the prior art so that high living polymerization property can beattained even if the polymerization is performed at a temperature nearerto room temperature.

[0065] It is preferred to perform the polymerization reaction accordingto the present invention in the atmosphere of an inert gas such asnitrogen, argon or helium. Furthermore, in order that the reactionsystem becomes uniform, it is preferred to perform the polymerizationunder a sufficient stirring condition.

[0066] In the polymerization reaction according to the presentinvention, the time necessary for the polymerization may beappropriately selected. According to the polymerization process of thepresent invention, however, the polymerization can be caused to advanceat a high speed. In the case that, for example, a methacrylic acid esteris used as the anionic polymerizable monomer, the polymerization can becompleted within several minutes although the time necessary for thepolymerization depends on adopted various conditions. In the case thatan acrylic acid ester is used as the anionic polymerizable monomer, thepolymerization can be completed within several tens of seconds.Accordingly, the polymerization reaction according to the presentinvention can be performed by “continuous tube reactor polymerization”,which has high productivity and good cooling efficiency.

[0067] In the present invention, the polymerization reaction can bestopped by adding a polymerization terminator to the reaction mixture,as in known anionic polymerization, at the stage when a target polymerchain is formed by the polymerization reaction. As the polymerizationterminator, a protic compound such as methanol, acetic acid or asolution of a hydrochloric acid in methanol may be used. The amount ofthe polymerization terminator is not especially limited. In general, itis preferred that the polymerization terminator is used in an amount of1 to 100 moles per mole of the anionic polymerization initiator used asthe polymerization initiator.

[0068] In the present invention, a terminal functional group supplyingagent (for example, aldehyde, lactone or carbon dioxide) may be added tothe reaction system after complete finish of the given polymerizationand before the addition of the polymerization terminator. In this case,it is possible to obtain a polymer having, at the terminal of itsmolecular chain, a functional group such as a hydroxyl group or acarboxyl group.

[0069] If metal components originating from the used anionicpolymerization initiator or the organoaluminum compound (A) remain inthe polymer obtained by separation from the reaction mixture wherein thepolymerization has been stopped, a drop in physical properties of thepolymer or a material using the polymer, a deterioration in transparencythereof, or the like may arise. For some purposes of the use of thepolymer, therefore, it is preferred to remove the metal compoundsoriginating from the used anionic polymerization initiator or theorganoaluminum compound (A) after the finish of the polymerization. Anefficient method for removing the metal compounds is a method ofsubjecting the polymer to cleaning treatment such as washing treatmentwith an acidic solution or adsorbing treatment with an adsorbent such asan ion-exchange resin. Examples of the acidic solution that can be usedinclude hydrochloric acid, aqueous sulfuric acid solution, aqueousnitric acid solution, aqueous acetic acid solution, aqueous propionicacid solution, and aqueous citric acid solution.

[0070] The method for separating a polymer from the reaction mixtureafter the polymerization is stopped is not especially limited and can beadopted from all known methods. For example, it is possible to adopt amethod comprising pouring the reaction mixture into a poor solvent for apolymer to precipitate the polymer, a method comprising distilling out asolvent from the reaction mixture to obtain a polymer, or the like.

[0071] According to the present invention, it is possible to produce apolymer having any molecular weight. The molecular weight of a polymerthat can be produced extends over a wide range. From the viewpoints ofhandling performances, fluidity and mechanical properties of theresultant polymer, and the like, it is in general preferred that thenumber-average molecular weight is from 1000 to 1000000. According tothe present invention, a polymer having high molecular weight uniformity(that is, a narrow molecular weight distribution) can be usuallyobtained. Thus, it is possible to produce a polymer having a molecularweight distribution (Mw/Mn) of 1.5 or less. It is however possible toobtain intentionally a polymer having a wide molecular weightdistribution by controlling the addition speed of the anionicpolymerizable monomer to the polymerization system, the diffusion rateof the monomer inside the polymerization system, or the like.

[0072] The present invention will be more specifically describedhereinafter by way of working examples, but the present invention is notlimited to these examples.

[0073] In these examples and the like, used chemicals were dried andpurified in the usual way, and were then deaerated with nitrogen. Thetransportation and supply of the chemicals were performed in theatmosphere of nitrogen.

EXAMPLE 1

[0074] An agitating stick with a half-moon shaped wing was set in athree-necked flask having a inner volume of 1 liter, and then theatmosphere inside the system was replaced by nitrogen. Into this flaskwere added 300 ml of toluene, 2.7 g of 1,2-dimethoxyethane and 40 ml ofa toluene solution containing 20.0 mmoles ofdiisobutyl(2,6-di-t-butyl-4-methylphenoxy)aluminum. The resultantsolution was cooled to −30° C. To this solution was added 1.54 ml of acyclohexane solution containing 2.0 mmoles of sec-butyllithium, and theresultant solution was stirred for 20 minutes.

[0075] While the solution was being vigorously stirred, 20.0 g of methylmethacrylate was dropwise added to this solution at −30° C. over about 3minutes. The solution first colored to yellow. After 1 minutes from theend of the addition by the dropping, the solution faded. After 3 minutesfrom the end of the addition by the dropping, 5 ml of methanol was addedthereto, so that the polymerization reaction was stopped.

[0076] The resultant solution was poured into 3 liters of methanol toprecipitate the resultant polymer and recover the polymer.

[0077] The yield of the resultant polymer (poly(methyl methacrylate))was about 100%. The molecular weight of the resultant polymer reduced topolystyrene was measured by GPC (gel permeation chromatography). As aresult, the Mn (number-average molecular weight) thereof was 34700, andthe Mw/Mn (molecular weight distribution) thereof was 1.10. It was alsofound that the polymerization initiation efficiency thereof was 0.29.

[0078] Polymerization conditions and polymerization results are shown inTable 1 described later.

EXAMPLE 2

[0079] A polymerization manner and a polymerization termination mannerwere performed in the same way as in Example 1 except that 28 ml of atoluene solution containing 14.0 mmoles ofisobutylbis(2,6-di-t-butyl-4-methylphenoxy)aluminum was used as asolution of an organoaluminum compound in toluene instead of 40 ml ofthe toluene solution containing 20.0 mmoles ofdiisobutyl(2,6-di-t-butyl-4-methylphenoxy)aluminum; 0.77 ml of acyclohexane solution containing 1.0 mmole of sec-butyllithium was usedas a solution of sec-butyllithium in cyclohexane instead of 1.54 ml ofthe cyclohexane solution containing 2.0 mmoles of sec-butyllithum; thetemperature upon the polymerization was changed from −30° C. to 0° C.;the amount of the anionic polymerizable monomer (methyl methacrylate)was changed from 20.0 g to 10.0 g; and the time for the polymerization(the time from the end of addition of the monomer to the termination ofthe polymerization) was changed from 3 minutes to 80 minutes.

[0080] The yield of the resultant polymer (poly(methyl methacrylate))was about 100%. The Mn of the resultant polymer was 10600, and the Mw/Mnthereof was 1.06. The polymerization initiation efficiency thereof was0.94.

[0081] Polymerization conditions and polymerization results are shown inTable 1 described later.

EXAMPLE 3

[0082] A polymerization manner and a polymerization termination mannerwere performed in the same way as in Example 2 except that the amount of1,2-dimethoxyethane was changed to 8.1 g and other polymerizationconditions were changed as shown in Table 1.

[0083] The yield of the resultant polymer (poly(methyl methacrylate))was about 100%. The Mn of the resultant polymer was 9800, and the Mw/Mnthereof was 1.06. The polymerization initiation efficiency thereof was1.02.

[0084] Polymerization conditions and polymerization results are shown inTable 1 described later.

EXAMPLE 4

[0085] A polymerization manner and a polymerization termination mannerwere performed in the same way as in Example 2 except that 1.0 mmole ofN,N,N′,N′-tetramethylethylenediamine was used instead of 2.7 g of1,2-dimethoxyethane and other polymerization conditions were changed asshown in Table 1.

[0086] The yield of the resultant polymer (poly(methyl methacrylate))was about 100%. The Mn of the resultant polymer was 12500, and the Mw/Mnthereof was 1.06. The polymerization initiation efficiency thereof was0.80.

[0087] Polymerization conditions and polymerization results are shown inTable 1 described later.

EXAMPLE 5

[0088] A polymerization manner and a polymerization termination mannerwere performed in the same way as in Example 1 except that 22 ml of atoluene solution containing 11.0 mmoles ofisobutylbis(2,6-di-t-butyl-4-methylphenoxy)aluminum was used as asolution of an organoaluminum compound in toluene instead of 40 ml ofthe toluene solution containing 20.0 mmoles ofdiisobutyl(2,6-di-t-butyl-4-methylphenoxy)aluminum; 0.77 ml of acyclohexane solution containing 1.0 mmole of sec-butyllithium was usedas a solution of sec-butyllithium in cyclohexane instead of 1.54 ml ofthe cyclohexane solution containing 2.0 mmoles of sec-butyllithium; thekind and the amount of the anionic polymerizable monomer were changedfrom methyl methacrylate and 20.0 g, respectively, to n-butyl acrylateand 10.0 g, respectively; and the time for the polymerization (the timefrom the end of addition of the monomer to the termination of thepolymerization) was changed from 3 minutes to 1 minute.

[0089] The yield of the resultant polymer (poly(n-butyl acrylate)) wasabout 100%. The Mn of the resultant polymer was 11600, and the Mw/Mnthereof was 1.08. The polymerization initiation efficiency thereof was0.86.

[0090] Polymerization conditions and polymerization results are shown inTable 1 described later.

EXAMPLE 6

[0091] A polymerization manner and a polymerization termination mannerwere performed in the same way as in Example 5 except that 11.0 mmolesof isobutylbis(2,6-di-t-butyl-4-methylphenoxy)aluminum was changed tothe same mmoles of ethylbis(2,6-di-t-butyl-4-methylphenoxy)aluminum.

[0092] The yield of the resultant polymer (poly(n-butyl acrylate)) wasabout 100%. The Mn of the resultant polymer was 14200, and the Mw/Mnthereof was 1.21. The polymerization initiation efficiency thereof was0.70.

[0093] Polymerization conditions and polymerization results are shown inTable 1 described later.

EXAMPLE 7

[0094] A polymerization manner and a polymerization termination mannerwere performed in the same way as in Example 5 except that 1.0 mmole ofN,N,N′,N′-tetramethylethylenediamine was used instead of 2.7 g of1,2-dimethoxyethane.

[0095] The yield of the resultant polymer (poly(n-butyl acrylate)) wasabout 100%. The Mn of the resultant polymer was 14800, and the Mw/Mnthereof was 1.05. The polymerization initiation efficiency thereof was0.68.

EXAMPLE 8

[0096] A polymerization manner and a polymerization termination mannerwere performed in the same way as in Example 5 except that 5.4 g ofdiethyl ether was used instead of 2.7 g of 1,2-dimethoxyethane.

[0097] The yield of the resultant polymer (poly(n-butyl acrylate)) wasabout 100%. The Mn of the resultant polymer was 14000, and the Mw/Mnthereof was 1.23. The polymerization initiation efficiency thereof was0.71.

[0098] Polymerization conditions and polymerization results are shown inTable 1 described later.

Reference Example 1

[0099] A polymerization manner and a polymerization termination mannerwere performed in the same way as in Example 1 except that the use of1,2-dimethoxyethane was omitted and the polymerization time was extendedfrom 3 minutes to 120 minutes. However, no polymer was recovered.

[0100] Polymerization conditions and polymerization results are shown inTable 1 described later.

Reference Example 2

[0101] A polymerization manner and a polymerization termination mannerwere performed in the same way as in Example 2 except that the use of1,2-dimethoxyethane was omitted and the polymerization time was extendedfrom 80 minutes to 120 minutes. However, no polymer was recovered.

[0102] Polymerization conditions and polymerization results are shown inTable 1 described later.

Reference Example 3

[0103] A polymerization manner and a polymerization termination mannerwere performed in the same way as in Example 5 except that the use of1,2-dimethoxyethane was omitted and the polymerization time was extendedfrom 1 minutes to 120 minutes.

[0104] The yield of the resultant polymer (poly(n-butyl acrylate)) wasabout 52%. The Mn of the resultant polymer was 17600, and the Mw/Mnthereof was 1.66. The polymerization initiation efficiency thereof was0.30.

[0105] Polymerization conditions and polymerization results are shown inTable 1 described later.

Reference Example 4

[0106] A polymerization manner and a polymerization termination mannerwere performed in the same way as in Example 1 except that 40 ml of atoluene solution containing 20.0 mmoles of triisobutylaluminum was usedas a solution of an organoaluminum in toluene instead of 40 ml of thetoluene solution containing 20.0 mmoles ofdiisobutyl(2,6-di-t-butyl-4-methylphenoxy)aluminum and thepolymerization time was extended from 3 minutes to 120 minutes. However,no polymer was recovered.

[0107] Polymerization conditions and polymerization results are shown inTable 1 described later.

Reference Example 5

[0108] A polymerization manner and a polymerization termination mannerwere performed in the same way as in Example 5 except that 1.0 mmole oftetramethylammonium chloride was used instead of 2.7 g of1,2-dimethoxyethane and the polymerization time was extended from 1minute to 120 minutes. The added tetramethylammonium chloride was hardlydissolved and during the polymerization insoluble substances wererecognized in the polymerization system.

[0109] The yield of the resultant polymer (poly(n-butyl acrylate)) wasabout 32%. The Mn of the resultant polymer was 15200, and the Mw/Mnthereof was 1.50. The polymerization initiation efficiency thereof was0.21.

[0110] Polymerization conditions and polymerization results are shown inTable 1 described later. TABLE 1 Polymerization conditions Polymer-Polymerization results ization Lewis Organoaluminum Polymerizationinitiator base compound Temp. Time Yield Mw/ initiation (mmoles) (% ormmoles) (mmoles) Monomer (g) (° C.) (min.) (%) Mn Mn efficiency Example1 s-BLi 2.0 DME    1.0% iB2Al(BHT) 20.0 MMA 20.0 −30 3 100 34700 1.100.29 Example 2 s-BLi 1.0 DME    1.0% iBAl(BHT)2 14.0 MMA 10.0 0 80 10010600 1.06 0.94 Example 3 s-BLi 1.0 DME    3.0% iBAl(BHT)2 14.0 MMA 10.00 40 100 9800 1.06 1.02 Example 4 s-BLi 1.0 TMEDA 1.0 iBAl(BHT)2 14.0MMA 10.0 0 45 100 12500 1.06 0.80 mmole Example 5 s-BLi 1.0 DME    1.0%iBAl(BHT)2 11.0 nBA 10.0 −30 1 100 11600 1.08 0.86 Example 6 s-BLi 1.0DME    1.0% EtAl(BHT)2 11.0 nBA 10.0 −30 1 100 14200 1.21 0.70 Example 7s-BLi 1.0 TMEDA 1.0 iBAl(BHT)2 11.0 nBA 10.0 −30 1 100 14800 1.05 0.68mmole Example 8 s-BLi 1.0 Et₂O    2.0% iBAl(BHT)2 11.0 nBA 10.0 −30 1100 14000 1.23 0.71 Reference s-BLi 2.0 — — iB2Al(BHT) 20.0 MMA 20.0 −30120 Not polymerized Example 1 Reference s-BLi 1.0 — — iBAl(BHT)2 14.0MMA 10.0 0 120 Not polymerized Example 2 Reference s-BLi 1.0 — —iBAl(BHT)2 11.0 nBA 10.0 −30 120 52 17600 1.66 0.30 Example 3 References-BLi 2.0 DME    1.0% iB3Al 20.0 MMA 20.0 −30 120 Not polymerizedExample 4 Reference s-BLi 1.0 Me₄NCl 1.0 iBAl(BHT)2 11.0 nBA 10.0 −30120 32 15200 1.50 0.21 Example 5 mmole

[0111] Symbols in the above Table 1 have the following meanings.

[0112] s-BLi: sec-butyllithium,

[0113] DME: 1,2-dimethoxyethane,

[0114] TMEDA: N,N,N′,N′-tetramethylethylenediamine,

[0115] Et₂O: diethyl ether,

[0116] Me₄NCl: tetramethylammonium chloride,

[0117] iB2Al(BHT): diisobutyl(2,6-di-t-butyl-4-methylphenoxy)aluminum,

[0118] iBAl(BHT)2: isobutylbis(2,6-di-t-butyl-4-methylphenoxy)aluminum,

[0119] EtAl(BHT)2: ethylbis(2,6-di-t-butyl-4-methylphenoxy)aluminum,

[0120] iB3Al: triisobutylaluminum,

[0121] MMA: methyl methacrylate, and

[0122] nBA: n-butyl acrylate.

[0123] It can be understood from the results shown in Table 1 that evenif in the polymerization processes in Examples 1-8 according to thepresent invention, polymerization of the polar anionic polymerizablemonomer was performed under a mild cooling temperature condition of −30°C. or 0° C. using sec-butyllithium suitable for industrial use as ananionic polymerization initiator, the desired polymer having a narrowmolecular weight distribution (Mw/Mn=1.05-1.23) was able to be producedwith a high yield (100%) for a short polymerization time (1-80 minutes).Moreover, it can be understood that the polymerization initiatorefficiency in these polymerization processes was relatively high(0.29-1.02) and in the case of using the organoaluminum compound (A-1)as the organoaluminum compound (A), the polymerization initiatorefficiency was especially high (0.68-1.02).

[0124] On the other hand, it can be understood that even if the extendedpolymerization time (120 minutes) was adopted in the polymerizationprocesses of Reference Examples 1-3, which were different from thepresent invention in that the addition of any Lewis base was omitted,polymerization did not advance substantially (Reference Examples 1 and2). Alternatively, even in the case wherein the monomer was polymerized(Reference Example 3), the molecular weight distribution of theresultant polymer was relatively wide (Mw/Mn=1.66) and the yield of thepolymer was low (52%). Besides, the polymerization initiation efficiencythereof was relatively low (it was 0.68-0.86 in Examples 5, 7 and 8 butit was 0.30 in Reference Example 3). It can be understood that even ifthe extended polymerization time (120 minutes) was adopted in ReferenceExample 4, which was different from the present invention in that anorganoaluminum compound having no chemical structure represented byAl—O—Ar as an organoaluminum compound was used, polymerization did notadvance substantially. It can also be understood that even if theextended polymerization time (120 minutes) was adopted in ReferenceExample 5, which was different from the present invention in that anorganoquaternary salt (tetramethylammonium chloride) was used instead ofthe ether compound or tertiary polyamine compound, the molecular weightdistribution of the resultant polymer was relatively wide (Mw/Mn=1.50)and the yield of the polymer was low (32%). Besides, the polymerizationinitiation efficiency thereof was also relatively low (it was 0.68-0.86in Examples 5,7 and 8 but it was 0.21 in Reference Example 5).

EXAMPLE 9 Example of Two-stage Polymerization of n-butyl Acrylate

[0125] As will be specifically described below, in the present example,n-butyl acrylate was polymerized at −30° C. (the first stagepolymerization), and after the polymerization, the resultant waspreserved at the same temperature for 1 hour. Thereafter, the secondstage polymerization was performed at −30° C. by adding n-butyl acrylatethereto.

[0126] (1) An agitating stick with a half-moon shaped wing was set in athree-necked flask having a inner volume of 1 liter, and then theatmosphere inside the system was replaced by nitrogen. Into this flaskwere added 300 ml of toluene, 2.7 g (30 mmoles) of 1,2-dimethoxyethaneand 22 ml of a toluene solution containing 11.0 mmoles ofisobutylbis(2,6-di-t-butyl-4-methylphenoxy)aluminum. The resultantsolution was cooled to −30° C. To this solution was added 0.77 ml of acyclohexane solution containing 1.0 mmole of sec-butyllithium, and theresultant solution was stirred for 20 minutes.

[0127] While the solution was being vigorously stirred, 10.0 g ofn-butyl acrylate was dropwise added to this solution at −30° C. overabout 3 minutes. The solution first colored to yellow. After 1 minutesfrom the end of the addition by the dropping, the solution faded.

[0128] (2) A part of the solution was sampled after 1 minute from theend of the addition by the dropping. The conversion of the monomer wasmeasured. As a result, it was proved that the conversion was about 100%.The molecular weight of the resultant polymer (poly(n-butyl acrylate))reduced to polystyrene was measured by GPC. As a result, it was foundthat the Mn thereof was 14000 and the Mw/Mn thereof was 1.09.

[0129] (3) The solution obtained in the above-mentioned item (1) waskept at −30° C. under stirring for 1 hour after the end of the additionby the dropping. Thereafter, 30.0 g of n-butyl acrylate was added tothis solution to perform polymerization at −30° C. for 1 hour. Next, 5ml of methanol was added thereto, so as to terminate the polymerizationreaction.

[0130] (4) The solution obtained in the above-mentioned item (3) waspoured into 3 liters of methanol, and then the resultant polymer wasprecipitated and recovered.

[0131] The yield of the resultant polymer (poly(n-butyl acrylate)) wasabout 100%. The molecular weight of the resultant polymer reduced topolystyrene was measured by GPC. As a result, it was found that the Mnthereof was 56700 and the Mw/Mn thereof was 1.04. According to the GPCmeasurement, no peak was observed near the molecular weight of thepolymer obtained by the first stage polymerization in theabove-mentioned item (1). This fact demonstrates that the deactivationrate of the living polymer during the preservation from the end of thefirst stage polymerization in the above-mentioned item (1) to the startof the second stage polymerization in the above-mentioned item (3) wasabout 0% and its living polymerization property was kept at a highlevel.

[0132] The results are shown in Table 2.

[0133]FIG. 1 shows a GPC chart of the polymer obtained by the secondstage polymerization.

Examples 10-17 Examples of Two-stage Polymerization of n-butyl Acrylate

[0134] In the present examples, the same first stage polymerizationmanner, preservation manner, second stage polymerization manner andpolymerization termination manner as in Example 9 were performed exceptthat conditions shown in Table 2 were adopted as the kind and the addedamount of used Lewis bases, and the temperature upon all periods of thefirst stage polymerization, the preservation (1 hour) and the secondstage polymerization.

[0135] The results are shown in Table 2. TABLE 2 Polymerization Resultsof the conditions and first stage preservation conditions polymerizationDeactiva- Conver- Tempera- tion rate sion of ture upon during monomer atpolymeri- the the second zation preserva- stage and tion polymeri- Lewisbase preservation period zation (mmoles) (° C.) Mn Mw/Mn (%) (%) ExampleDME 30 −30 14000 1.09 0 100 9 Example DME 30 0 12000 1.12 41 100 10Example DME 150 0 11000 1.25 22 100 11 Example Diglyme 30 0 14000 1.2229 100 12 Example 12- 1.0 0 22000 1.27 32 100 13 Crown-4 Example TMEDA3.0 0 18000 1.27 39 100 14 Example PMDETA 3.0 0 13000 1.22 23 100 15Example HMTETA 3.0 0 12000 1.22 8 100 16 Example PMDETA 5.0 20 130001.26 55 100 17

[0136] Symbols in the above Table 2 have the following meanings.

[0137] DME: 1,2-dimethoxyethane,

[0138] Diglyme: diethylene glycol dimethyl ether,

[0139] TMEDA: N,N,N′,N′-tetramethylethylenediamine,

[0140] PMDETA: N,N,N′,N″,N″-pentamethyldiethylenetriamine, and

[0141] HMTETA: 1,1,4,7,10,10-hexamethyltriethylenetetraamine.

[0142] It can be understood from the results shown in Table 2 that evenif 0° C. or a temperature near room temperature, which was a highertemperature than that in Example 9. was adopted as the temperature uponall periods of the first stage polymerization, the preservation and thesecond stage polymerization, the deactivation rate of the living polymerduring the preservation was kept in the range of 55% or less in thepolymerization processes in Examples 10-17 according to the presentinvention. Thus, it can be understood that the polymerization reactionadvanced completely even in the second stage polymerization after thepreservation.

Reference Example 6 Example of Two-stage Polymerization of n-butylAcrylate

[0143] As will be specifically described below, in the present ReferenceExample, n-butyl acrylate was polymerized at −30° C. (the first stagepolymerization), and after the polymerization, the resultant waspreserved at the same temperature for 1 hour. Thereafter, the secondstage polymerization was performed at −30° C. by adding n-butyl acrylatethereto.

[0144] (1) The same first stage polymerization as in the item (1) ofExample 9 was performed except that 0.63 ml of a cyclohexane solutioncontaining 1.0 mmole of t-butyllithium was used instead of 0.77 ml ofthe cyclohexane solution containing 1.0 mmole of sec-butyllithium andthe addition of the 1,2-dimethoxyethane was omitted.

[0145] (2) A sample was collected from the solution obtained in theabove-mentioned item (1) and was then measured in the same way as in theitem (2) of Example 9. As a result, it was proved that the yield of theresultant polymer (poly(n-butyl acrylate)) was about 100%, the Mnthereof was 18800 and the Mw/Mn thereof was 1.25. According to the GPCmeasurement, tailing was slightly observed at the low molecular weightside.

[0146] (3) In the same way as in the item (3) of Example 9, the solutionobtained in the above-mentioned item (1) was kept at −30° C. for 1 hour,and then the second polymerization and polymerization termination wereperformed.

[0147] (4) In the same way as in the item (4) of Example 9, a polymer(poly(n-butyl acrylate)) was recovered from the solution obtained in theabove-mentioned item (3) and was then measured. As a result, it wasfound that the yield of the polymer was 59% and the conversion of themonomer at the second stage polymerization in the above-mentioned item(3) was 45%. The Mn of the resultant polymer was 27800, and the Mw/Mnthereof was 1.60. A peak corresponding to the polymer obtained by thefirst stage polymerization in the above-mentioned item (1) wasconsiderably recognized. The rate of the area of the peak to that of thewhole polymer was about 17%. It can be estimated from this fact that thedeactivation rate of the living polymer during the preservation from theend of the first stage polymerization in the above-mentioned item (1) tothe start of the second stage polymerization in the above-mentioned item(3) was about 40%.

[0148]FIG. 2 shows a GPC chart of the polymer obtained by the secondstage polymerization.

EXAMPLE 18 Example of a Block Copolymer of n-butyl Acrylate and MethylMethacrylate

[0149] As will be specifically described below, in the present example,n-butyl acrylate was polymerized, and subsequently methyl methacrylatewas added thereto so as to perform copolymerization.

[0150] (1) n-Butyl acrylate was polymerized in the same manner as in theitem (1) of Example 9 except that the amount of sec-butyllithium waschanged from 1.0 mmole to 1.4 mmoles.

[0151] (2) A sample was collected from the solution obtained in theabove-mentioned item (1) after 1 minute from the addition by thedropping of n-butyl acrylate, and was then measured in the same way asin the item (2) of Example 9. As a result, it was proved that the yieldof the resultant polymer (poly(n-butyl acrylate)) was about 100%, the Mnthereof was 9300 and the Mw/Mn thereof was 1.06.

[0152] A curve (a) of FIG. 3 shows a GPC chart of the polymer obtainedby the first stage polymerization in the above-mentioned item (1).

[0153] (3) The solution obtained in the above-mentioned item (1) waskept at −30° C. under stirring for 1.5 hour after the addition of thedropping. Thereafter, 30.0 g of methyl methacrylate was added to thissolution, and then polymerization was performed at −30° C. for 6 hours.Next, 5 ml of methanol was added thereto, so as to terminate thepolymerization reaction.

[0154] (4) The solution obtained in the above-mentioned item (3) waspoured into 3 liters of methanol, to precipitate and recover theresultant polymer.

[0155] The yield of the polymer (poly(n-butyl acrylate-b-methylmethacrylate)) was about 75% and the conversion of methyl methacrylatein the above-mentioned item (3) was about 66%. The molecular weight ofthe resultant polymer reduced to polystyrene was measured by GPC. As aresult, it was found that the Mn thereof was 18500 and the Mw/Mn thereofwas 1.05. According to the GPC measurement, no peak was observed nearthe molecular weight of the polymer obtained by the first stagepolymerization in the above-mentioned item (1). This fact demonstratesthat the deactivation rate of the living polymer during the preservationfrom the end of the first stage polymerization in the above-mentioned(1) to the start of the second stage polymerization in theabove-mentioned (3) was about 0% and a block copolymer having a veryhigh block efficiency was obtained.

[0156] A curve (b) of FIG. 3 shows a GPC chart of the polymer obtainedby the second stage polymerization.

[0157] As is evident from the above-mentioned examples, according to theanionic polymerization process of the present invention, a highpolymerization initiation efficiency, a high polymerization rate and ahigh living polymerization property can be attained even if an anionicpolymerizable monomer is polymerized, using an anionic polymerizationinitiator suitable for industrial use, under a relatively mild coolingtemperature condition or a condition of a temperature near roomtemperature. According to the present invention, it is also possible toproduce a polymer having a narrow molecular weight distribution and ablock copolymer having a high block efficiency with industrialprofitability.

What is claimed is:
 1. An anionic polymerization process, characterizedin that when an anionic polymerizable monomer is polymerized with ananionic polymerization initiator, a tertiary organoaluminum compound (A)having in the molecule thereof a chemical structure represented by ageneral formula: Al—O—Ar wherein Ar represents an aromatic ring, and atleast one Lewis base (B) selected from the group consisting of an ethercompound and a tertiary polyamine compound are caused to be present inthe polymerization system wherein the polymerization is performed. 2.The anionic polymerization process according to claim 1, wherein theanionic polymerization initiator is an organolithium compound having achemical structure having a secondary carbon atom as a central anionicion.
 3. The anionic polymerization process according to claim 1, whereinthe anionic polymerizable monomer is a polar anionic polymerizablemonomer.
 4. The anionic polymerization process according to claim 3,wherein the polar anionic polymerizable monomer is an α, β-unsaturatedcarboxylic acid ester compound, an α, β-unsaturated carboxylic acidamide compound, or an α, β-unsaturated ketone compound.
 5. The anionicpolymerization process according to claim 1, wherein the Lewis base (B)is the ether compound.
 6. The anionic polymerization process accordingto claim 1, wherein the ether compound is a cyclic ether compound havingin the molecule thereof two or more ether bonds, or an acyclic ethercompound having in the molecule thereof one or more ether bonds.
 7. Theanionic polymerization process according to claim 1, wherein the Lewisbase (B) is the tertiary polyamine compound.
 8. A process for producinga polymer, which comprises polymerizing an anionic polymerizable monomerby the anionic polymerization process according to claim
 1. 9. A processfor producing a block copolymer, which comprises polymerizing two ormore anionic polymerizable monomers by the anionic polymerizationprocess according to claim 1.